Alexithymia as impairment in constructing the internal representation of emotional stimuli

Alexithymia is a personality trait characterized by difficulties in processing emotional stimuli. Here, Experiment1 shows that alexithymia has a significant impact on everyday life, being related to lower emotional intelligence, empathy and wellbeing. Experiment2 shows that alexithymia is related to the need for more emotional intensity to identify fear in facial expressions. Although these experiments contribute to the literature describing the difficulties of alexithymia, the basic mechanisms underlying such difficulties remain poorly understood. For this reason, the remaining of this thesis focuses on investigating whether differences in emotional learning may characterize alexithymia. Indeed, through emotional learning the internal representation of stimuli is shaped, so that neutral stimuli acquire emotional value. Impairment in this process has been reported in clinical conditions marked by difficulties in emotion processing; nevertheless, this has never been investigated in alexithymia. Given this, Experiment3 shows that alexithymia is related to impairment in learning the aversive value of stimuli, evidenced by reduced physiological markers of emotional prediction in Pavlovian threat conditioning. On the contrary, Experiment4 did not find such evidence, when learning appetitive value. Nevertheless, evidence for impairment in learning the appetitive value of stimuli was found in Experiment5, where electrophysiological markers of prediction and prediction error were assessed during Pavlovian reward conditioning. Finally, Experiment 6 examined the ability to learn the emotional value of actions during instrumental learning, and to use this learned value for adaptive behavior in a new context. Here, alexithymia was related to a difficulty in learning from punishment, marked by longer response time when having to avoid stimuli, which had previously acquired aversive value, encountered in a new context. Together, these results indicate impairment in emotional learning in alexithymia, which may be more severe for aversive than appetitive stimuli. The new insight provided by these results for the understanding of alexithymia is discussed.